Yulian Khagi, M.D., from the University of California San Diego Moores Cancer Center in La Jolla, and colleagues assessed 69 patients with diverse malignancies who received checkpoint inhibitor-based immunotherapy and blood-derived ctDNA next-generation sequencing testing of 54 to 70 genes. Based on total and variants of unknown significance (VUS) alterations, the rates of stable disease for at least six months, partial and complete response (PR and CR), progression-free survival (PFS), and overall survival (OS) were assessed.

The researchers found that significant improvement in PFS was seen for high versus low alteration number in VUS (greater than three versus three or fewer alterations), with stable disease for at least six months/PR/CR of 45 and 15 percent, respectively. The results were similar for high versus low total alteration number (characterized plus VUS, greater than or equal to six versus fewer than six). High VUS alteration status also correlated with statistically significant OS improvement. Responders versus nonresponders with VUS greater than three had a median PFS of 23 versus 2.3 months in two-month landmark analysis.

“Given the association of alteration number on liquid biopsy and checkpoint inhibitor-based immunotherapy outcomes, further investigation of hypermutated ctDNA as a predictive biomarker is warranted,” the authors write.

Several authors disclosed financial ties to the biopharmaceutical industry.